How to Change the Oil in a 2020 Yamaha YZ250X: Step-by-Step Guide

Shop parts for a 2020 Yamaha YZ250X Dirt Bike.

Keeping your 2020 Yamaha YZ250X in top condition starts with routine maintenance, and one of the most essential tasks is changing the gearbox oil. Below is MotoSport.com–s proprietary, detailed procedure tailored for this two-stroke dirt bike model. Unlike four-strokes, your YZ250X gearbox uses separate oil for the clutch and transmission, not the engine. Follow these expert steps to get it right every time.

Tools & Supplies You–ll Need

  • 12mm socket or wrench (for the drain bolt)
  • Oil catch pan
  • Funnel (preferably with a long spout)
  • Rags or paper towels (for cleaning up spills)
  • Measuring cup (to measure oil quantity)
  • Fresh transmission oil (Yamaha recommends a high-quality transmission oil; check your owner–s manual for the preferred type and viscosity—usually 10W-30 or 80W)
  • New copper crush washer (recommended but not required every time)
  • Gloves (to keep your hands clean and safe)

Oil Change Steps for Your YZ250X

  • Warm up the engine. Start the bike and let it idle for three to five minutes. This helps the oil thin out, allowing more contaminants to drain and ensuring a more complete oil change.
    Note: Never drain oil when the engine is hot enough to cause burns—let it cool until just warm.
  • Stabilize the bike. Shut the engine off and position the YZ250X upright, ideally using a bike stand to keep it level and secure during the process.
  • Remove the oil fill cap. Locate the oil fill cap on the right side of the engine. Remove it now to help oil drain faster and more completely.
  • Drain the gearbox oil. Locate the 12mm drain bolt at the bottom of the crankcase on the left side. Place your oil catch pan directly underneath, and carefully loosen and remove the bolt.
    Let the old oil drain completely. Check the oil for signs of water (milky appearance) or metal shavings—either could indicate a problem that requires further inspection.
    Specific to the YZ250X: There is no oil filter, as this is a two-stroke transmission oil change, not an engine oil change.
  • Inspect and replace the drain bolt washer. Check the copper crush washer for wear or deformation. Replace it if it looks flattened or cracked, as a fresh washer helps ensure a tight seal and prevents leaks.
  • Reinstall the drain bolt. Once all oil has drained, thread the drain bolt (with a new washer if possible) by hand to avoid cross-threading. Then tighten it securely with your wrench. Do not overtighten; the recommended torque can be found in the owner–s manual—usually around 10-12 ft-lbs (13-16 Nm).
  • Add fresh oil. Using your funnel, carefully pour in the correct amount of new transmission oil:
    • 2020 YZ250X oil capacity: 0.75 liters (approximately 0.80 US quarts) for a full change.
    Use your measuring cup for accuracy and avoid overfilling.
    Pro tip: Pour slowly to make sure you don–t spill.
  • Replace and secure the oil fill cap.
  • Check for leaks and proper level. With the bike still upright, wipe down the engine, start it briefly, then shut it off and recheck the oil level using the sight glass if equipped (or dipstick, if applicable—note, the YZ250X typically relies on quantity).
  • Dispose of old oil responsibly. Take the used oil to a certified recycling center.

2020 Yamaha YZ250X-Specific Oil Change Call-Outs

  • No oil filter: Unlike four-stroke engines, your two-stroke YZ250X does not have (or require) a replaceable oil filter for the transmission/gearbox. Just change the oil at factory-recommended intervals.
  • Watch for milky oil: If the drained oil appears milky, coolant may be contaminating the gearbox due to a faulty seal—address this immediately as it can lead to expensive engine damage.
  • Short oil life: Aggressive riding, wet/muddy conditions, or frequent clutch use can shorten oil life. Change the oil more often if you ride hard or race regularly.
  • Never use engine oil: Only use manufacturer-recommended transmission oil for the YZ250X gearbox. Do not substitute with typical four-stroke or automotive engine oil.

Final Checklist Before You Ride

  • Ensure all tools are removed from the work area.
  • Double-check the drain bolt and fill cap for tightness.
  • Wipe down any oil drips or spills.
  • Test ride slowly, then check again for any signs of a leak.

Changing the oil regularly on your 2020 Yamaha YZ250X helps ensure smooth shifting, longer clutch and gearbox life, and better overall performance on the track or trail. Trust MotoSport.com for all your maintenance parts, oils, and accessories to keep your ride performing at its best.

Related Shopping Categories

Shop Motor Oil for a 2020 Yamaha YZ250X Dirt Bike.

Shop Oil Filters for a 2020 Yamaha YZ250X Dirt Bike.

Shop Oil Drain Pans for a 2020 Yamaha YZ250X Dirt Bike.

Shop Tools for a 2020 Yamaha YZ250X Dirt Bike.

Shop Oil Fillers and Drain Plugs for a 2020 Yamaha YZ250X Dirt Bike.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.